Recently, as imaging apparatuses used for medical imaging or non-destructive inspection using X rays, radiation imaging apparatuses using a flat panel detector (hereinafter referred to as “FPD”) have been put into practical use. Certain radiation imaging apparatuses using more than one flat panel detector (i.e., using a plurality of FPDs) have also been proposed. Such imaging apparatuses are used, for example, in the field of medical imaging, as digital imaging apparatuses for still-image radiography, such as radiographic imaging, or for moving-image radiography, such as fluoroscopy.
Concerning radiation imaging apparatuses using a plurality of FPDs, patent literature (PTL) document 1 discloses a photoelectric conversion apparatus including a plurality of substrates (each corresponding to the above-mentioned FPDs) disposed adjacent to each other; each substrate includes a plurality of two-dimensional photoelectric conversion elements. In the photoelectric conversion apparatus described in PTL 1, at least one of scanning circuits and detection circuits are disposed at two opposing sides of the photoelectric conversion apparatus, and the scanning directions of the circuits disposed at the two sides can be set to be the same. In PTL 1, the plurality of FPDs are disposed adjacent to each other in accordance with a predetermined positional relationship.
PTL 2 discloses the use of plural FPDs improve imaging efficiency by using the following technique. A first X-ray tube and a first X-ray detection circuit are used to capture first image data. Additionally, a second X-ray tube and a second X-ray detection circuit are used to capture second image data. Then, the obtained first image data and second image data are subjected to computing processing so as to generate a tomographic image or three-dimensional image of a subject. In PTL 2, the first X-ray detection circuit and the second X-ray detection circuit are disposed perpendicular to each other, such that they cross at right angles with each other in accordance with a predetermined positional relationship.
In the imaging systems using a plurality of FPDs disclosed in the above-described PTL 1 and PTL 2, it is assumed that the FPDs have the same structure or a symmetrical arrangement and are disposed at fixed positions in accordance with a predetermined positional relationship.
However, when constructing an imaging system using a plurality of FPDs which can independently perform an imaging operation (obtaining images) and which can be positioned as desired, the positional relationship of the FPDs is not decided upon in advance. Accordingly, mismatching in the scanning methods among the FPDs, such as inconsistencies in the scanning directions, may occur depending on the positional relationship of the FPDs, which may impair the continuity of a plurality of images obtained from the individual FPDs. Also, if the driving time is different among the plurality of FPDs, mismatching in the scanning methods among the FPDs may also occur, which may impair the continuity of a plurality of images obtained from the individual FPDs. Thus, when a plurality of images obtained from the plurality of FPDs are synthesized, artifacts may occur in the images, which may decrease the image quality.